Synthesis of homologous compounds Fe2O3(ZnO)m (m=6, 8, 34) by various selective microwave heating conditions

Homologous compounds, Fe2O3(ZnO)m, with a modulated natural superlattice structure, were synthesized within 10 min at 1200 °C in a simple solid-state reaction under 2.45 and 28 GHz microwave irradiation. Transmission electron microscopy and energy dispersive X-ray spectroscopy results revealed that m decreased with increasing the synthesis temperature and microwave frequency. In the Zn–Fe–O system, γ-Fe2O3 was heated in H and E-field and ZnO was heated in E-field under 2.45 GHz microwave irradiation. However, α, γ-Fe2O3 and calcined ZnO were heated under 28 GHz microwave irradiation. This selective microwave heating resulted in the different diffusion conditions than conventional heating; therefore, homologous compounds with low m values were rapidly synthesized at low temperature.